<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>原生JS实现购物车结算功能代码</title>
    <link rel="stylesheet" href="../css/style.css" />
</head>

<body>
    <div class="catbox">
        <table id="cartTable">
            <thead>
                <tr>
                    <th><label>
                            <input class="check-all check" type="checkbox" />&nbsp;&nbsp;全选</label></th>
                    <th>商品</th>
                    <th>单价</th>
                    <th>数量</th>
                    <th>小计</th>
                    <th>操作</th>
                </tr>
            </thead>
            <tbody>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/1.jpg" alt="" /><span>Casio/卡西欧 EX-TR350</span></td>
                    <td class="price">5999.88</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">5999.88</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/2.jpg" alt="" /><span>Canon/佳能 PowerShot SX50 HS</span></td>
                    <td class="price">3888.50</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">3888.50</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/3.jpg" alt="" /><span>Sony/索尼 DSC-WX300</span></td>
                    <td class="price">1428.50</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">1428.50</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/4.jpg" alt="" /><span>Fujifilm/富士 instax mini 25</span></td>
                    <td class="price">640.60</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">640.60</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
            </tbody>
        </table>
        <div class="foot" id="foot">

            <a class="fl" id="deleteAll" href="javascript:;">删除</a>
            <div class="fr closing" onclick="getTotal();">结 算</div>
            <input type="hidden" id="cartTotalPrice" />
            <div class="fr total">合计：￥<span id="priceTotal">0.00</span></div>
            <div class="fr selected" id="selected">已选商品<span id="selectedTotal">0</span>件<span
                    class="arrow up">︽</span><span class="arrow down">︾</span></div>
            <div class="selected-view">
                <div id="selectedViewList" class="clearfix">
                    <div><img src="../images/1.jpg"><span>取消选择</span></div>
                </div>
                <span class="arrow">◆<span>◆</span></span>
            </div>
        </div>
    </div>

</body>
<script>
    var catbox = document.getElementsByClassName("catbox")[0];
    var checkAll = document.getElementsByClassName("check-all")[0];
    var checkOneList = document.getElementsByClassName("check-one");


    catbox.onclick = function (e) {
        var e = e || window.event;
        var target = e.target || e.srcElement;

        if (target.classList.contains("check-all")) {
            checkAllHandler(target);
            getTotal();
        } else if (target.classList.contains("check-one")) {
            isAllChecked();
            getTotal();
        } else if (target.classList.contains("add")) {
            addHandler(target);
            getTotal();
        } else if (target.classList.contains("reduce")) {
            reduceHandler(target);
            getTotal();
        } else if (target.classList.contains("delete")) {
            deleteOneHandler(target);
            isAllChecked();
            getTotal();
        } else if (target.id == "deleteAll") {
            deleteAllHandler();
            isAllChecked();
            getTotal();
        }



    }

    function checkAllHandler(target) {
        var status = target.checked;
        console.log(status);
        // 所有单选跟随全选的选中状态
        for (var i = 0; i < checkOneList.length; i++) {
            var checkOne = checkOneList[i];
            checkOne.checked = status;
        }
    }
    function addHandler(target) {
        // a. 输入框  数量 加一 
        var countInput = target.previousElementSibling;
        console.log(countInput);
        var num = countInput.value;  // num = "1"   => 把 countInput.value 取出来 赋值给变量num
        num++;
        console.log(num);
        countInput.value = num;  // 把num赋值到countInput 

        // b. 小计更新  =  单价*数量
        // 单价  =>  找  加号的父元素的前一个
        // 数量  =>  num

        var priceTd = target.parentElement.previousElementSibling;
        var subtotalTd = target.parentElement.nextElementSibling;

        console.log(priceTd);
        var price = priceTd.textContent;
        // 价格可能出现的情况
        // "2999.00元"   => "2999"
        // "¥2999.00"    => "2999"

        var subtotal = price * num;
        subtotalTd.textContent = subtotal.toFixed(2);


        var reduce = countInput.previousElementSibling;
        reduce.textContent = "-";
    }
    function reduceHandler(target) {
        //a. 输入框  数量 减一
        var countInput = next(target);
        var num = countInput.value;
        // c. 减之前  判断 如果数量已经为1  不能减     return false
        if (num <= 1) {
            alert("亲,不能再少了!")
            return false; // 如果数量已经是1 => 不再执行后续操作
        }

        num--;  //自减

        // 减之后  判断  如果数量为1  减号按钮的 “-” 消失   (2切1的瞬间)
        if (num <= 1) target.textContent = "";

        countInput.value = num;

        // b.  小计更新  =  单价*数量 
        var priceTd = prev(parent(target));
        var subtotalTd = next(parent(target));
        var price = priceTd.textContent;

        var subtotal = price * num;
        subtotalTd.textContent = subtotal.toFixed(2);

    }
    function deleteOneHandler(target) {
        if (confirm("是否删除当前商品?")) {
            // var parentTr = this.parentElement.parentElement;
            var parentTr = parent(parent(target));
            parentTr.remove();
        }
    }
    function deleteAllHandler() {
        for (var i = 0; i < checkOneList.length; i++) {
            var checkOne = checkOneList[i];
            if (checkOne.checked) {
                var parentTr = parent(parent(checkOne));
                parentTr.remove();
                i--;
            }
        }
    }





    // 判断商品是否反选 (可以是删除之后剩余的) 
    function isAllChecked() {
        // 全删之后判断是否 取消反选
        var flag = true; //假设全部被选中

        // 点击单选时 => 判断所有的单选是否全部被选中
        for (var j = 0; j < checkOneList.length; j++) {
            var item = checkOneList[j];

            // !item.checked === true  =>   item.checked === false
            if (!item.checked) { // 如果存在未选中的 => false
                flag = false;
                break;
            }
        }

        // 2. 如果全部删除 => 商品数量为0  => checkOneList.length === 0 => false
        checkAll.checked = checkOneList.length > 0 ? flag : false;
    }

    function getTotal() {
        var sum = 0;
        var allPrice = 0;
        for (var j = 0; j < checkOneList.length; j++) {
            var item = checkOneList[j];
            if (item.checked) {
                var parentTr = parent(parent(item));
                var countInput = parentTr.getElementsByClassName("count-input")[0];
                var subtotalTd = parentTr.getElementsByClassName("subtotal")[0];
                var num = countInput.value * 1;
                var subtotal = subtotalTd.textContent * 1;
                console.log(countInput, num);

                sum += num;
                allPrice += subtotal;

            }
        }
        // console.log(sum,allPrice);

        selectedTotal.textContent = sum;
        priceTotal.textContent = allPrice.toFixed(2);
    }

    function parent(ele) {
        return ele.parentElement;
    }

    function prev(ele) {
        return ele.previousElementSibling;
    }

    function next(ele) {
        return ele.nextElementSibling;
    }



</script>

</html>